Fix 3and3 and 4and4 rules

They were buggy when applied close to corners. New version is rewritten
from scratch.
Fix bug where the game isn't passing exception on

Illegal actions is to be handled further down the chain.
Rewrite victory check using new count function

TIL about the scope of protected. Didn't think I could access that
function.
Add TWL-based BoardWidget to codebase

The widget is not yet included in the state.
Use new BoardWidget instead of BoardComponent

Required adding listeners to Boards, which in turn required the
BoardPacket to be modified as we don't want to send listeners over the
net.
AbstractComponent not needed
Fix initial position of scrollbars